It is now well recognized that it is important to conserve water and that toilet flushing in the home is a major user of fresh water. Further, it is well known that a "normal" quantity of flush water, e.g., on the order of 4 gallons, or, in newer units, 3.5 gallons, is sometimes necessary to adequately empty the waste material but that a greatly reduced amount of water, e.g., 1 to 1.5 gallons, is quite adequate under some circumstances which need not be described in detail.
With this knowledge, various efforts have been made to develop an apparatus capable of selectively dispensing one of two or more possible quantities of water from the amount available in the usual storage tank. Following are U.S. Patents illustrating the diverse paths taken to achieve a goal somewhat similar to that described above and, in some cases, identical: Nos.
2,526,294: Stegeman PA1 2,532,977: White PA1 2,674,744: White PA1 2,813,274: Lewis et al. PA1 2,939,152: Wood PA1 3,108,286: Moore PA1 3,121,880: Gelhar PA1 3,156,930: Moulton et al. PA1 3,334,359: Weingarten PA1 3,380,077: Armstrong PA1 3,839,746: Kowaiski PA1 3,908,204: Hopkins PA1 3,945,056: Kowaiski PA1 3,969,775: Haselton PA1 4,014,050: Goldsworthy PA1 4,058,858: Liao Che-Wei PA1 4,080,669: Biggerstaff PA1 4,141,091: Pulvari
Scrutiny of the above will reveal that each attempt to solve the problem suffers from one or more of several shortcomings, including (a) requiring that a significant portion of the mechanism within the tank be either replaced or greatly modified (b) employing techniques which are marginally workable, at best, and which can be expected to be unreliable after a very short time because of the water immersion of the components (c) using devices such as compression coil springs which are known to have a short life in a tank or (d) in the case of electricity operated devices, placing current-carrying components in a position which presents a possible shock hazard.
While modification of the tank-contained valve operating mechanism is not, in itself, necessarily undesirable, the fact is that most homeowners hesitate to materially alter a flushing apparatus which works well, however wastefully, and manufacturers hesitate to modify and sell a system which has found wide market acceptance and has been proven reliable.